School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
Int J Biol Macromol. 2019 Dec 1;141:21-28. doi: 10.1016/j.ijbiomac.2019.08.241. Epub 2019 Aug 29.
The production optimization, partial characterization and properties of an exopolysaccharide (EPS) from Lactobacillus sakei L3 were performed. Sucrose concentration, initial pH and inoculation volume were the most significant variables that improved the L3 EPS production in a three-level Plackett-Burman design. The maximum EPS yield of 69.65 g/L (2.16-fold greater than the original yield) was obtained under optimal conditions of 127.80 g/L sucrose, initial pH 6.87 and 3.15% inoculation volume. Chemical analyses revealed that the observed EPS bioactivity was mainly due to the sugar moieties. The chain conformation was characterized by the Congo red test, a β-elimination reaction and circular dichroism, which indicated that the L3 EPS exhibited a random coil structure and O-linkages in aqueous solution, and the EPS concentration did not alter the EPS chain conformation but did modify the hydrogen-bond interactions and chirality of the polysaccharide. The purified L3 EPS exhibited high water solubility, probiotic effects and emulsification activity. The L3 EPS at 2.0 mg/mL formed a highly active and stable emulsion with sunflower oil, with EA, ES, ES and ES indices of 62.30 ± 0.06%, 57.95 ± 0.18%, 42.73 ± 0.26% and 43.05 ± 0.08%, respectively. These results collectively describe a high-yield EPS with unique characteristics for exploitation in large-scale industrial food applications.
对清酒乳杆菌 L3 胞外多糖（EPS）进行了生产优化、部分特性分析和性能研究。在三水平 Plackett-Burman 设计中，蔗糖浓度、初始 pH 和接种量是提高 L3 EPS 产量的最显著变量。在 127.80 g/L 蔗糖、初始 pH 6.87 和 3.15%接种量的最佳条件下，获得了 69.65 g/L 的最大 EPS 产量（比原始产量高 2.16 倍）。化学分析表明，观察到的 EPS 生物活性主要归因于糖部分。刚果红试验、β-消除反应和圆二色性对链构象进行了表征，表明 L3 EPS 在水溶液中呈现无规卷曲结构和 O-键，EPS 浓度不会改变 EPS 链构象，但会改变多糖的氢键相互作用和手性。纯化的 L3 EPS 具有高水溶性、益生菌作用和乳化活性。在 2.0 mg/mL 时，L3 EPS 与葵花油形成了高度活性和稳定的乳液，其 EA、ES、ES 和 ES 指数分别为 62.30±0.06%、57.95±0.18%、42.73±0.26%和 43.05±0.08%。这些结果共同描述了一种具有独特特性的高产 EPS，可用于大规模工业食品应用的开发。
